Used to eval python expressions containing arbitrary fully-qualified package names, automatically importing packages as needed.

autoimport.py

 from collections import defaultdict
 from importlib import import_module
 
 def autoimport_eval(term):
    '''
    Used to eval any expression containing fully-qualified names, such as
    'torchvision.models.alexnet(pretrained=True)' with automatic import of
    global module names.
    '''

    class DictNamespace(object):
        def __init__(self, d):
            self.__d__ = d
        def __getattr__(self, key):
            return self.__d__[key]

    class AutoImportDict(defaultdict):
        def __init__(self, parent=None):
            super().__init__()
            self.parent = parent
        def __missing__(self, key):
            if self.parent is not None:
                key = self.parent + '.' + key
            if hasattr(__builtins__, key):
                return getattr(__builtins__, key)
            mdl = import_module(key)
            # Return an AutoImportDict for any namespace packages
            if hasattr(mdl, '__path__') and not hasattr(mdl, '__file__'):
                return DictNamespace(AutoImportDict(key))
            return mdl

    return eval(term, {}, AutoImportDict())